STM32L152- sometimes problems with wakeup

[andreas239955_stm1]

Posted on July 23, 2015 at 15:30

After working our instrument goes in the sleep-mode (__WFI) to save power. With a key, which is connected to the Wakeup-pin, we can switch back in the operation mode. Sometimes this function does not work. In this case the CPU is in a strange status and we have to disconnect/connect the battery.

I suppose that CPU is still running in internal ROM (may be internal Bootloader), because I can stop debuging at address 0x1ff008fe.

I don't generate a reset to invoke Pin BOOT0, BOOT1.

Have anyone an idea for this behaviour?

[Amel NASRI]

Posted on July 24, 2015 at 12:35

Hi kneissl.andreas,

1- How often the issue is faced? In which circumstance? 

2- ''In this case the CPU is in a strange status''. What is meant by ''strange status''?

3- I suggest you have a look to some available examples & compare your code with the one in these examples. You may refer to the one under STM32Cube_FW_L1_V1.2.0\Projects\STM32L152RE-Nucleo\Examples\PWR\PWR_SLEEP.

-Mayla-

[andreas239955_stm1]

Posted on July 27, 2015 at 10:50

Hi Mayla,

many thanks for your response. In the meanwhile we have detected the cause. It was a hardware problem. If we wakeup the instrument and the battery power is very low, a pin of the RS232-interface is floating. This pin is connected with the bootloader pin of the CPU and can be LOW or HIGH at the moment, the instrument is switched ON. So the CPU goes in the bootloader state and we have the problem.